Silicon rubber color paste and color master batch without flow marks and color marks and preparation method of silicon rubber color paste and color master batch

Abstract

The invention relates to the technical field of rubber color master batches, in particular to a silicone rubber color paste and color master batch without flow marks and color marks and a preparation method of the silicone rubber color paste and color master batch. The silicone rubber color paste comprises the following raw materials in parts by weight: 80-100 parts of a first carrier, 10-30 parts of a filler, 60-80 parts of a pigment, 1-3 parts of an auxiliary agent and 1-5 parts of a first additive, the silicone rubber color master batch comprises the following raw materials in parts by weight: 80-100 parts of a second carrier, 10-30 parts of a filler, 60-80 parts of a pigment, 1-3 parts of an auxiliary agent and 1-5 parts of a second additive. The silicone rubber color paste and the color master batch disclosed by the invention are excellent in dispersity during application, overcome color defects such as flow marks and color marks, are good in compatibility and stability, have certain functionality, and are low in cost and good in applicability.

Description

Technical Field

[0001] The invention relates to the technical field of rubber masterbatches, and in particular to a silicone rubber color paste and masterbatch without flow marks and color marks, and a preparation method thereof. Background Art

[0002] With the rapid development of modern manufacturing, silicone rubber has been widely used in many industries due to its excellent biocompatibility, temperature resistance, chemical inertness and insulation properties. According to the different physical states, silicone rubber is often divided into two types: liquid and solid. Liquid silicone rubber has good fluidity and fast curing characteristics, which is particularly suitable for the production of precision parts. In the medical field, it can be used to prepare micro-catheters, and in the electronics industry, it can accurately replicate complex mold structures. In addition, this material can perfectly display delicate design elements when making daily necessities such as exquisite tableware, baby products, elastic toys and creative mobile phone cases. Solid silicone rubber is known for its high mechanical strength and is often used in the production of industrial seals and functional buttons. In daily life, this type of material is the preferred choice for manufacturing products such as kitchenware, baby products, 3C digital products, anti-slip products and sports mats, ensuring the durability and functionality of the products.

[0003] In actual production, the coloring process for silicone rubber products often faces significant problems. During the injection molding process, if the flow rate of liquid silicone rubber fluctuates or the mold structure is complex, uneven flow can easily produce flow marks, resulting in streaky color differences. This phenomenon is particularly prominent in products with high appearance requirements, such as silicone tableware, baby products, and mobile phone cases, and can directly affect the product's aesthetics and market value. More seriously, because liquid silicone rubber flows under high pressure, colorants (such as color pastes, color slurries, or masterbatches) easily separate from the substrate. If the dispersion is insufficient, the colorant will aggregate to form localized color blocks, resulting in inconsistent color depth and seriously affecting the color uniformity of the product. Silicone rubber products also face the problem of color streaking during the coloring process. Due to the different temperature resistance of different colorants (such as color pastes, color slurries, or masterbatches), different degrees of discoloration will occur during high-temperature vulcanization. When multiple colorants with different temperature resistance are mixed, water-ripple-like color marks are prone to appear on the product surface. If the molding temperature exceeds the colorant's tolerance limit, the colorant will also decompose or severely discolor, further exacerbating the color streak phenomenon. The coloring process of solid silicone rubber also faces challenges. The dispersion of the colorant directly affects the consistency of the product appearance. This phenomenon is particularly evident in products with dark or highly saturated colors (such as military green, red, and orange).

[0004] The coloring defects of silicone rubber products have become an important issue that restricts the development of the industry. These color unevenness phenomena directly lead to an increase in the defective rate of products and a sharp increase in production costs. Especially in high-end application fields with almost stringent requirements on appearance quality - such as consumer electronics, medical equipment and fine daily necessities, slight color differences may cause quality disputes, thereby affecting brand reputation and market competitiveness. Based on this, overcoming the problems of color flow marks, color marks and pigment agglomeration of silicone rubber products has become a key technical bottleneck that needs to be broken through in order to achieve high-quality development of the industry. Therefore, it is particularly important to disclose a silicone rubber color paste and masterbatch without flow marks and color marks. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention discloses a silicone rubber color paste and masterbatch free of flow and color marks, as well as methods for preparing the same. The silicone rubber color paste and masterbatch disclosed herein exhibit excellent dispersibility during application, overcoming color defects such as flow and color marks, while also exhibiting excellent compatibility and stability, along with certain functionality, low cost, and excellent applicability.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A first aspect of the present invention provides a silicone rubber color paste without flow marks and color marks, wherein the silicone rubber color paste comprises the following raw materials in parts by weight: 80 to 100 parts of a first carrier, 10 to 30 parts of a filler, 60 to 80 parts of a pigment, 1 to 3 parts of an auxiliary agent, and 1 to 5 parts of a first additive; wherein the first carrier is methyl silicone oil.

[0008] A second aspect of the present invention provides a silicone rubber masterbatch without flow marks and color marks, the silicone rubber masterbatch comprising the following raw materials in parts by weight: 80 to 100 parts of a second carrier, 10 to 30 parts of a filler, 60 to 80 parts of a pigment, 1 to 3 parts of an auxiliary agent and 1 to 5 parts of a second additive; wherein the second carrier is methyl vinyl rubber.

[0009] In some embodiments of the present invention, the fillers are all fumed silica.

[0010] In some embodiments of the present invention, the auxiliary agents are all dispersants.

[0011] In some embodiments of the present invention, the dispersant is a polymer dispersant and / or a small molecule dispersant.

[0012] In some embodiments of the present invention, the dispersant is obtained by mixing a high molecular weight dispersant and a low molecular weight dispersant in a mass ratio of (0.1-0.3):1.

[0013] In some embodiments of the present invention, the small molecule dispersant is stearic acid or a stearate.

[0014] In some embodiments of the present invention, the preparation steps of the polymer dispersant are as follows:

[0015] (1) Add N,N-dimethyl-1,3-propylenediamine and 1,2-cyclohexanediol diglycidyl ether to anhydrous ethanol in sequence, stir and mix evenly under ice bath conditions, then heat to 40-50°C under an inert atmosphere for 20-24 hours, and obtain an intermediate product after post-treatment;

[0016] (2) Under an inert atmosphere, the intermediate product of step (1) and caprolactone are mixed, the temperature is raised to 120-135° C., a catalyst is added, and the mixture is reacted for 4-7 hours. After post-treatment, a polymer dispersant is obtained.

[0017] In some embodiments of the present invention, in step (1), the mass ratio of N,N-dimethyl-1,3-propylenediamine to 1,2-cyclohexanediol diglycidyl ether is 1:(1.35-1.8).

[0018] In some embodiments of the present invention, in step (2), the mass ratio of the intermediate product to caprolactone is 1:(12-15).

[0019] In some embodiments of the present invention, the first additive is vinyl silicone oil.

[0020] In some embodiments of the present invention, the second additive is hydroxy silicone oil.

[0021] The present invention introduces a main chain containing an anchoring group by reacting N,N-dimethyl-1,3-propylenediamine and 1,2-cyclohexanediol diglycidyl ether, and then uses polycaprolactone as a stabilizing chain segment to prepare a polymer dispersant with rich and concentrated anchoring groups, strong adsorption effect, and excellent dispersion stability.

[0022] This invention introduces abundant anchoring groups into the dispersant, which bind to active sites on the pigment particle surface through van der Waals forces, thereby preventing pigment particle aggregation. Simultaneously, the introduction of caprolactone allows the chain segments to extend into the silicone rubber matrix, forming a spatial barrier that prevents pigment particles from agglomerating, increasing compatibility and avoiding flow anomalies caused by phase separation and pigment agglomeration, which in turn prevents flow and color marks. The presence of a rigid backbone structure enhances the color durability and uniformity of color pastes and masterbatches during application, preventing yellowing and mitigating the degradation of silicone rubber performance often associated with aging of color pastes, masterbatches, and color pastes.

[0023] The present invention also uses a compound of a high molecular weight dispersant and a small molecular weight dispersant to achieve the synergistic effect of rapid adsorption and steric hindrance at a relatively low cost, thereby increasing the dispersion stability of the color paste and masterbatch and having excellent applicability.

[0024] Another aspect of the present invention provides a method for preparing silicone rubber color paste and masterbatch without flow marks and color marks, comprising the following steps:

[0025] Silicone rubber color paste: add the first carrier, filler, pigment, auxiliary agent and first additive into a vacuum stirring disperser and disperse for 20 to 40 minutes, grind and fill to obtain the silicone rubber color paste;

[0026] Silicone rubber masterbatch: Mix the second carrier, filler, pigment, auxiliary agent and second additive in an internal mixer for 20 to 40 minutes, grind, tablet and cut into pieces to obtain silicone rubber masterbatch.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention avoids color defects such as flow marks and color marks by adding specific dispersants to silicone rubber color paste and color masterbatch respectively, increases the compatibility and stability of silicone rubber color paste and color masterbatch, and also has certain functionality, low cost and good applicability.

[0029] (2) The present invention introduces a main chain containing an anchoring group by reacting N,N-dimethyl-1,3-propylenediamine and 1,2-cyclohexanediol diglycidyl ether, and then uses polycaprolactone as a stabilizing chain segment to prepare a polymer dispersant with rich and concentrated anchoring groups, strong adsorption effect, excellent dispersion stability and excellent applicability.

[0030] (3) The present invention introduces abundant anchoring groups into the dispersant and adsorbs them to the active sites on the surface of the pigment particles through van der Waals forces, thereby preventing the aggregation of the pigment particles. At the same time, the introduction of caprolactone allows the chain segments to extend into the silicone rubber matrix to form a spatial barrier, preventing the pigment particles from agglomerating, increasing compatibility, and avoiding flow anomalies due to phase separation and pigment agglomeration, thereby avoiding flow marks and color marks.

[0031] (4) The presence of a rigid structure on the main chain of the polymer dispersant of the present invention helps to increase the color durability and uniformity of the color paste and masterbatch during application, avoids yellowing, and indirectly reduces the problem of silicone rubber performance degradation caused by aging of the color paste and masterbatch.

[0032] (5) The present invention achieves the synergistic effect of rapid adsorption and steric hindrance at a relatively low cost by compounding a polymer dispersant and a small molecule dispersant, thereby increasing the dispersion stability of silicone rubber color paste and masterbatch, and having excellent applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the main view of the special mold one;

[0034] Figure 2 This is the main view of the special mold 2;

[0035] Figure 3 For Example 10 ( Figure 3 Left) and Example 1 ( Figure 3 Schematic diagram of the sample (right);

[0036] In the figure: 1. Special mold 1; 2. Special mold 2; 3. Glue inlet; 4. Ribbon. DETAILED DESCRIPTION

[0037] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples are examples of the present invention and are only used to illustrate the present invention, but are not intended to limit the present invention. At the same time, all professional terms mentioned below have the same meaning as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Other combinations and various improvements within the scope of the present invention can be made without departing from the gist or scope of the present invention.

[0038] Unless otherwise specified, the following reagents can be easily obtained from commercial companies. The pigment used is phthalocyanine green (PG7), pigment yellow (PY.180) and carbon black (PB7) mixed in a mass ratio of 1:0.6:0.1; the particle size of the fumed silica used is 15-20 nm; the methyl silicone oil (201) used is purchased from Shandong Luderui New Materials Co., Ltd.; the viscosity (25 ° C) of the vinyl silicone oil used is 10000 mm 2 / s, vinyl content of 8.0 mol%; the methyl vinyl rubber (MY 110) used was purchased from Anhui Mingyi Silicon Industry Co., Ltd.; the viscosity (25 ° C) of the hydroxyl silicone oil used was 25mm 2 / s, the hydroxyl content is 8.5wt%; the polyethylene wax used is CERALENE 691.

[0039] Unless otherwise specified, the post-processing steps used below, such as “grinding,” “filling,” “cutting,” “reduced pressure distillation,” “column chromatography,” “purification,” and “drying,” are routine operations for those skilled in the art and can be selected based on actual operations.

[0040] Preparation Example 1

[0041] The preparation steps of polymer dispersant are as follows:

[0042] (1) 10 g of N,N-dimethyl-1,3-propylenediamine and 15.6 g of 1,2-cyclohexanediol diglycidyl ether were added to 100 mL of anhydrous ethanol in sequence, stirred and mixed evenly in an ice bath, and then heated to 45°C under a nitrogen atmosphere for 22 h. The intermediate product was obtained by vacuum distillation and column chromatography.

[0043] (2) Under nitrogen atmosphere, 0.5 g of the intermediate product of step (1) and 6.75 g of caprolactone were mixed, the temperature was raised to 130° C., 0.02 g of dibutyltin dilaurate was added, and the mixture was reacted for 5.5 h. After cooling to room temperature, the mixture was dissolved in chloroform, precipitated with ether, purified, and dried to obtain a polymer dispersant.

[0044] Preparation Example 2

[0045] The preparation steps of the polymer dispersant are the same as those in Preparation Example 1, except that in step (1) of this Preparation Example, the amount of 1,2-cyclohexanediol diglycidyl ether added is 19 g.

[0046] Preparation Example 3

[0047] The preparation steps of the polymer dispersant are the same as those in Preparation Example 1, except that the amount of caprolactone added in step (2) in this Preparation Example is 8 g.

[0048] Example 1

[0049] A silicone rubber color paste with no flow marks or color marks comprises the following raw materials in parts by weight: 90 parts of methyl silicone oil, 20 parts of fumed silica, 70 parts of pigment, 2 parts of dispersant (prepared by mixing a polymer dispersant and zinc stearate in a mass ratio of 0.2:1), and 3 parts of vinyl silicone oil.

[0050] The method for preparing a silicone rubber color paste without flow marks and color marks in this embodiment comprises the following steps:

[0051] Methyl silicone oil, fumed silica, pigment, polymer dispersant, zinc stearate and vinyl silicone oil are added into a vacuum stirring disperser and dispersed for 30 minutes. The silicone rubber color paste is obtained by grinding and filling.

[0052] The polymer dispersant used in this example is obtained from Preparation Example 1.

[0053] Example 2

[0054] A silicone rubber color paste with no flow marks or color marks comprises the following raw materials in parts by weight: 80 parts of methyl silicone oil, 10 parts of fumed silica, 60 parts of pigment, 1 part of dispersant (prepared by mixing a polymer dispersant and zinc stearate in a mass ratio of 0.2:1), and 1 part of vinyl silicone oil.

[0055] The method for preparing a silicone rubber color paste without flow marks and color marks in this embodiment comprises the following steps:

[0056] Methyl silicone oil, fumed silica, pigment, polymer dispersant, zinc stearate and vinyl silicone oil are added into a vacuum stirring disperser and dispersed for 20 minutes. The silicone rubber color paste is obtained by grinding and filling.

[0057] The polymer dispersant used in this example is obtained from Preparation Example 1.

[0058] Example 3

[0059] A silicone rubber color paste with no flow marks or color marks comprises the following raw materials in parts by weight: 100 parts of methyl silicone oil, 30 parts of fumed silica, 80 parts of pigment, 3 parts of dispersant (prepared by mixing a polymer dispersant and zinc stearate in a mass ratio of 0.2:1), and 5 parts of vinyl silicone oil.

[0060] The method for preparing a silicone rubber color paste without flow marks and color marks in this embodiment comprises the following steps:

[0061] Methyl silicone oil, fumed silica, pigment, polymer dispersant, zinc stearate and vinyl silicone oil are added into a vacuum stirring disperser and dispersed for 40 minutes. The silicone rubber color paste is obtained by grinding and filling.

[0062] The polymer dispersant used in this example is obtained from Preparation Example 1.

[0063] Example 4

[0064] A silicone rubber color paste without flow marks and color marks and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the polymer dispersant used is obtained from Preparation Example 2.

[0065] Example 5

[0066] A silicone rubber color paste without flow marks and color marks and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the polymer dispersant used is obtained from Preparation Example 3.

[0067] Example 6

[0068] A silicone rubber color paste without flow marks and color marks and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the dispersant is obtained by mixing a polymer dispersant and zinc stearate in a mass ratio of 0.4:1.

[0069] Example 7

[0070] A silicone rubber color paste without flow marks and color marks and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that an equal amount of polyethylene wax is used to replace the polymer dispersant obtained in Preparation Example 1.

[0071] Example 8

[0072] A silicone rubber masterbatch without flow marks or color marks comprises the following raw materials in parts by weight: 90 parts of methyl vinyl rubber, 20 parts of fumed silica, 70 parts of pigment, 2 parts of dispersant (prepared by mixing a polymer dispersant and zinc stearate in a mass ratio of 0.2:1), and 3 parts of hydroxy silicone oil.

[0073] The method for preparing a silicone rubber masterbatch without flow marks and color marks in this embodiment comprises the following steps:

[0074] Methyl vinyl rubber, fumed silica, pigment, polymer dispersant, zinc stearate and hydroxy silicone oil are mixed in an internal mixer for 30 minutes, and then ground, sheeted and cut into pieces to obtain silicone rubber masterbatch.

[0075] The polymer dispersant used in this example is obtained from Preparation Example 1.

[0076] Example 9

[0077] A silicone rubber masterbatch without flow marks and color marks and a preparation method thereof. The specific implementation method is the same as that of Example 8, except that polyethylene wax replaces the polymer dispersant in an equal amount.

[0078] Example 10

[0079] A silicone rubber color paste without flow marks and color marks and a preparation method thereof. The specific implementation method is the same as that of Example 7, except that the pigment used is fluorescent fuchsin (RTS-21).

[0080] Performance Testing

[0081] The color pastes or masterbatches obtained in Examples 1-9 were prepared according to the patent CN116574381B and GB / T2941 to perform the following performance tests (1) and (2):

[0082] (1) UV aging resistance test: The UV aging test was carried out in accordance with the standard GB / T14522-1993, using a UV lamp with a wavelength of 280-315nm and an irradiation of 50W / m 2 , the aging time is 240h;

[0083] (2) Heat aging performance test: Heat aging test was carried out in accordance with the standard GB / T3512-1983, with an aging time of 120 h;

[0084] (3) Dispersion performance test: Take the color paste or masterbatch obtained in Examples 1-10 above and add it to the silicone rubber system at an addition amount of 1 wt%. Figure 1 ) and special mold 2( Figure 2 ) (Special mold 1 and special mold 2 are circular molds with a diameter of 100 mm; special mold 1 has a glue inlet 3 on each of the left and right sides; special mold 1 and special mold 2 have cross-shaped grid ribs) and vulcanized to obtain each specimen. The specimen was visually observed for color marks or flow marks:

[0085] 1) Color paste sample preparation: The color paste was added to commercially available liquid silicone rubber (Elkem LSR 9350-30, Shore A hardness of 30), stirred in a vacuum mixer until uniform, and then vacuumed. The mixture was then injected into a custom mold (shot size 58 g) through two side inlets 3 using a liquid injection machine. The mold was then pressed and vulcanized at 130°C for 100 seconds to obtain the sample.

[0086] 2) Preparation of color paste sample: The specific method is the same as that described in step 1), except that the commercially available liquid silicone rubber (Elkem liquid silicone rubber LSR 9350-60) with a Shore A hardness of 60 is used. The sample is obtained and the results are recorded in Example 11;

[0087] 3) Masterbatch Sample Preparation: Commercially available methyl vinyl rubber mix (Dow Corning 6011) was mixed in an open mill until uniform, and a dipentadiene curing agent (0.5% by weight of the commercially available methyl vinyl rubber mix) was added and mixed with the masterbatch until uniform. Sheets were formed, and 50 g of the sheet was weighed and cut on a cutting machine into slices 8 mm thick and 50 mm in diameter. The slices were evenly placed in a special mold 2, and then vulcanized on a flat plate vulcanizer at a mold temperature of 180°C for 150 seconds. The sheets were pressed to obtain the samples.

[0088] The specific test results are shown in Table 1:

[0089] Table 1

[0090]

[0091] As shown in Table 1, the color pastes provided in Examples 1 to 3 of the present invention and the color masterbatch provided in Example 8 have good dispersibility and excellent resistance to ultraviolet light and heat aging.

[0092] By comparing Example 4 and Example 5 with Example 1, it can be seen that when the addition amounts of 1,2-cyclohexanediol diglycidyl ether and caprolactone are changed respectively during the preparation of the polymer dispersant, the anchoring group may decrease, the adsorption effect is insufficient, and the dispersion effect on the pigment particles is weakened, resulting in phase separation and pigment agglomeration, flow marks and color marks. The latter is also affected by the rigid structure, resulting in varying degrees of decline in the system's UV resistance and thermal aging properties.

[0093] From the comparison between Example 6 and Example 1, it can be seen that when the ratio of zinc stearate and the polymer dispersant is changed during the mixing of the dispersants, the rapid adsorption effect on the pigment of the system is reduced, which affects the dispersion stability and causes flow marks.

[0094] By comparing Example 7 with Example 1, and Example 9 with Example 8, it can be seen that when the polymer dispersant obtained in Preparation Example 1 is replaced by an equal amount of polyethylene wax, its adsorption and steric hindrance in the color paste and masterbatch system are reduced, and the system's UV resistance and thermal aging performance are also reduced to varying degrees.

[0095] From Example 10 ( Figure 3 Left) and Example 1 ( Figure 3 (Right) Comparison shows that when polyethylene wax is used in equal amounts to replace the polymer dispersant obtained in Preparation Example 1 and fluorescent fuchsin (RTS-21) is selected as the pigment to prepare the silicone rubber color paste, color marks and flow marks appear in the complex mold specially prepared by the present invention, and obvious color marks and flow marks appear at the intersection of the opposite sides. In fact, fluorescent fuchsin (RTS-21) color paste is the pigment color paste system that is least likely to have color marks and flow marks in this field; and the mixed grass green color obtained by the pigment of Example 1 (phthalocyanine green (PG7), pigment yellow (PY.180) and carbon black (PB7) are mixed in a mass ratio of 1:0.6:0.1) is more prone to dispersion defects such as color marks and flow marks due to its high color complexity, but the sample prepared thereby has excellent color uniformity, without any color marks or flow marks. Comparison between the two further illustrates that the silicone rubber color paste masterbatch disclosed in the present invention has excellent dispersibility and can adapt to the application requirements of various complex mold products.

[0096] From the comparison between Example 11 and Example 1, it can be seen that the color paste has excellent dispersibility when applied to silicone rubber systems of different hardnesses, indicating that the color paste components of the present invention have excellent compatibility and stability and can be adapted to a variety of silicone rubber systems.

[0097] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A silicone rubber color paste without flow marks and color marks, characterized in that: The silicone rubber color paste comprises the following raw materials in parts by weight: 80 to 100 parts of a first carrier, 10 to 30 parts of a filler, 60 to 80 parts of a pigment, 1 to 3 parts of an auxiliary agent and 1 to 5 parts of a first additive; wherein the first carrier is methyl silicone oil.

2. A silicone rubber masterbatch without flow marks and color marks, characterized in that: The silicone rubber masterbatch comprises the following raw materials in parts by weight: 80 to 100 parts of a second carrier, 10 to 30 parts of a filler, 60 to 80 parts of a pigment, 1 to 3 parts of an auxiliary agent and 1 to 5 parts of a second additive; wherein the second carrier is methyl vinyl rubber.

3. The silicone rubber color paste and masterbatch without flow marks and color marks according to claim 1 or 2, characterized in that: The filler is fumed silica.

4. The silicone rubber color paste and masterbatch without flow marks and color marks according to claim 1 or 2, characterized in that: The dispersant is a polymer dispersant and / or a small molecule dispersant.

5. The silicone rubber color paste and masterbatch without flow marks and color marks according to claim 4, characterized in that: The dispersant is obtained by mixing a high molecular weight dispersant and a small molecular weight dispersant in a mass ratio of (0.1-0.3):

1.

6. The silicone rubber color paste and masterbatch without flow marks and color marks according to claim 4, characterized in that: The small molecule dispersant is stearic acid or stearate.

7. The silicone rubber color paste and masterbatch without flow marks and color marks according to claim 4, characterized in that: The preparation steps of the polymer dispersant are as follows: (1) Add N,N-dimethyl-1,3-propylenediamine and 1,2-cyclohexanediol diglycidyl ether to anhydrous ethanol in sequence, stir and mix evenly under ice bath conditions, then heat to 40-50°C under an inert atmosphere for 20-24 hours, and obtain an intermediate product after post-treatment; (2) Under an inert atmosphere, the intermediate product of step (1) and caprolactone are mixed, the temperature is raised to 120-135° C., a catalyst is added, and the mixture is reacted for 4-7 hours. After post-treatment, a polymer dispersant is obtained.

8. The silicone rubber color paste and masterbatch without flow marks and color marks according to claim 7, characterized in that: In step (1), the mass ratio of the N,N-dimethyl-1,3-propylenediamine to 1,2-cyclohexanediol diglycidyl ether is 1:(1.35-1.8).

9. The silicone rubber color paste and masterbatch without flow marks and color marks according to claim 7, characterized in that: In step (2), the mass ratio of the intermediate product to caprolactone is 1:(12-15).

10. A method for preparing the silicone rubber color paste and masterbatch without flow marks and color marks according to any one of claims 3 to 9, characterized in that: The following steps are involved: Silicone rubber color paste: add the first carrier, filler, pigment, auxiliary agent and first additive into a vacuum stirring disperser and disperse for 20 to 40 minutes, grind and fill to obtain the silicone rubber color paste; Silicone rubber masterbatch: Mix the second carrier, filler, pigment, auxiliary agent and second additive in an internal mixer for 20 to 40 minutes, grind, tablet and cut into pieces to obtain silicone rubber masterbatch.

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